<template>
  <div class="spec-preview">
    <img :src="showImage" />
    <div class="event" @mousemove="handler"></div>
    <div class="big">
      <img :src="showImage" ref="big" :style="{top:-2*y+'px',left:-2*x+'px'}"/>
    </div>
    <div class="mask" ref="mask" :style="{top:y+'px',left:x+'px'}"></div>
  </div>
</template>

<script>
  export default {
    name: "Zoom",
    data() {
      return {
        x:0,
        y:0,
      }
    },
    props:['skuImageList'],
    computed:{
      showImage(){
        let url='';
        this.skuImageList.forEach(item => {
          if(item.isDefault=='1'){
            url=item.imgUrl
          }
        });
        return url
      },
    },
    methods:{
      handler(e){
        let mask=this.$refs.mask.offsetWidth;
        this.x=e.offsetX-mask/2;
        this.y=e.offsetY-mask/2;
        if(this.x<0){
          this.x=0;
        }else if(this.x>mask){
          this.x=mask
        }
        if(this.y<0){
          this.y=0;
        }else if(this.y>mask){
          this.y=mask
        }
      }
    },
  }
</script>

<style lang="less">
  .spec-preview {
    position: relative;
    width: 400px;
    height: 400px;
    border: 1px solid #ccc;

    img {
      width: 100%;
      height: 100%;
    }

    .event {
      width: 100%;
      height: 100%;
      position: absolute;
      top: 0;
      left: 0;
      z-index: 998;
    }

    .mask {
      width: 50%;
      height: 50%;
      background-color: rgba(0, 255, 0, 0.3);
      position: absolute;
      left: 0;
      top: 0;
      display: none;
    }

    .big {
      width: 100%;
      height: 100%;
      position: absolute;
      top: -1px;
      left: 100%;
      border: 1px solid #aaa;
      overflow: hidden;
      z-index: 998;
      display: none;
      background: white;

      img {
        width: 200%;
        max-width: 200%;
        height: 200%;
        position: absolute;
        left: 0;
        top: 0;
      }
    }

    .event:hover~.mask,
    .event:hover~.big {
      display: block;
    }
  }
</style>